<?php

/*
 * This file is part of Twig.
 *
 * (c) 2009 Fabien Potencier
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

/**
 * Interface implemented by extension classes.
 *
 * @package    twig
 * @author     Fabien Potencier <fabien.potencier@symfony-project.com>
 * @version    SVN: $Id$
 */
interface Twig_ExtensionInterface
{
  /**
   * Initializes the runtime environment.
   *
   * This is where you can load some file that contains filter functions for instance.
   */
  public function initRuntime();

  /**
   * Returns the token parser instances to add to the existing list.
   *
   * @return array An array of Twig_TokenParser instances
   */
  public function getTokenParsers();

  /**
   * Returns the node visitor instances to add to the existing list.
   *
   * @return array An array of Twig_NodeVisitorInterface instances
   */
  public function getNodeVisitors();

  /**
   * Returns a list of filters to add to the existing list.
   *
   * @return array An array of filters
   */
  public function getFilters();

  /**
   * Returns the name of the extension.
   *
   * @return string The extension name
   */
  public function getName();
}
